| 摘要 |
PURPOSE: To provide the synchronization tracking circuit excellent in the precision of synchronization tracking at a reception station in a mobile communication system based on the code division multiplex connection system. CONSTITUTION: A signal to noise ratio measurement circuit 20 measures a signal to noise power ratio (S/N) of a received signal IN. A correlation length discrimination circuit 30 decides the length of a correlation block based on a relational table 32 describing cross reference between the S/N and the length of the correlation block among an Early pseudo random (PN) signal S47e, a rate PN signal S471, and a reception signal IN. A delay locked loop circuit 40 obtains respectively the correlation among the Early pseudo random (PN) signal S47e, the rate PN signal S471, and the reception signal IN based on the length of the correlation block from the correlation length discrimination circuit 30 to detect a shift in the phase of the reception signal based on the difference and to change the phase of the Early pseudo random (PN) signal S47e and the rate PN signal S471 thereby approaching a difference from each correlation to be zero and tracking the Early pseudo random (PN) signal and the rate PN signal synchronously with the reception signal IN. |
